...and small time rental house in Copenhagen.
I completely agree with Tobias... I think the primary reason that producers tell you no is not because you want to shoot on film, but because you don't have a sound reason to do so. None of the things you claim are true... and shooting on film will make your project less flexible.
Think about this... why are almost noone shooting film anymore? Heck... even Deakins will shoot digital and he does so because it fits the project he's working on best.
Roger Deakins shot "In Time" in HD and upscaled it to 4k afterwards.... did you notice?
The worst that could happen buying those would be that the fresnel lens isn't of high enough standart, or that the housing is cheaply made and falls apart over time. The tech behind the actual light is old school and hard to mess up.
But I would still prefer buying used Arri lights if available, they are build like tanks and will take a severe beating and still work.
Actually... if you want something like raw, but can live with the compromise of cheap lenses, and shooting on card in-camera, then the Eos M (the first one...) with Magic Lantern is the cheapest way to shoot raw. Have a look at the article here on the site.
You wont even get uncompressed from a 5D... it's 8 bit all the way, including if you install magiclantern, then it will still be 8 bit coming out of the camera.
Except.... the very first footage he shows doesnt look cinematic at all... its not particularly good looking on top of that.